The dirt on dirt: The importance of soil for having good healthy food


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It’s something you don’t usually think about when you sit down to a nice meal. Dirt. For one thing it ain’t that appetising to imagine a mud pie instead of your meat pie or a bowl of dirt instead of a bowl of dessert. Let me just eat my food, thank you very much.

But the reality is that without dirt you wouldn’t have food! Without good, healthy, nutritious dirt you can’t have good, healthy and nutritious food. Because the nutrients in your food are directly correlated to the nutrients available in the soil in which it was grown.

So we are pretty much eating dirt.

Being such the life giving substance that it is, it deserves to be treated with a bit more respect and tender loving care. So let’s get down and dirty to learn more about the lovely substance that is soil. 

This will be a quick run down and really doesn’t cover the breadth or scope of the intricacies in soil. Heck, soil science is still discovering things itself! There’s chemistry, biology, geology, hydrology and mineralogy all mixed up and involved in the study of soil so to really get a good knowledge of it you may just have to dedicate your life to it!

But nobody got time for that.

Anyway, back to eating dirt, ahem, soil.

Soil is formed through a number of factors such as climate, topography, the parent rock material, biological factors, and time. 

All this influences the fertility of the soil, it’s nutrient content and pH, as well as various biological and chemical characteristics. 

Volcanic soils for example are rich and lush, chocolatey brown, envied by all for its fabulous properties allowing for great crop production. As you can gather, these soils are produced from…volcanoes! The leftover broken down remains of lava flows from an either extinct or active volcano.

Unfortunately for us here in Australia, most of our soils are old and weather beaten, with not much nutrients remaining in them. We do have pockets of really nice soil, such as the Liverpool Plains region in North-West NSW, but these soils only cover a small % of the total Australian landmass.

As you can see, many soils, much confusion, but pretty colours. Source: ASRIS, CSIRO Australia

When plants are growing, they all require a certain amount of macro and micro nutrients to grow sufficiently. Just like us humans, the right diets keep them in their prime, in tip-top shape, but not enough leaves them deficient and impairs growth. Also like us too much of a good thing, like donuts or chocolate, can be bad. Though the plant equivalent would probably by phosphorus or nitrogen.

Mega appealing to plants, not so to us, phosphorus and nitrogen are two out of three essential macro-nutrients plants need. The third one is potassium. All these nutrients plants get through the soil.

If a soil is deficient in these nutrients (like a lot of Australian soils) then the plants won’t grow to their optimum level. Instead of the big-bulked up iceberg lettuce we are use to we’d instead get scrawny smaller, probably yellowed, lettuces instead.

Enter fertilisers. 

Fertilisers add nutrients to the soil for plants to utilise. Like a dose of medicine, fertilisers help aid the deficiencies of the soil. But again not all fertilisers are created equally, and depending on the fertiliser used, can in some cases further propagate problems rather then fixing them.

It depends on the speed of which a farmer desires results. If they want a quick-fix solution then modern fertilisers are the go, because these provide a big hit of readily available nutrients to the soil that the plants can rapidly access and utilise. Problem with a lot of modern fertilisers though is they disguise the problems of the soil, like a band-aid just aiding the wound for only a bit, but not actually allowing it to heal fully.


Image from Matthias Ripp, CC BY

The long-term result fertiliser scenario aims to heal the soil. To treat it with a long-term outlook so that the soil can support itself, not requiring additions from quick-fix fertilisers. Things such as manures, blood and bone, cover-crops and nitrogen-fixing plants are management practises that target the microbes and life in the soil, as mentioned before, to make nutrients more available. Yes they provide nutrients, but they make the soil work for it.

Just as the personal trainer yells at the gym “The more you train the stronger you get!” 

These fertilisers provide ‘locked-up’ chemical forms of nutrients as well as the microbes to unlock it. So by developing the microbes the nutrients are slowly unlocked, all the whilst the microbial life community of the soil flourishes with the resources the fertilisers provide. Results in the plants will take longer to show compared to the other modern fertilisers, but it’s effects are longer lasting as the soil itself is more capable of providing nutrients.

But by nourishing the soil in this way you can propagate all the good things. Those aforementioned microbes? They are the good things. The more life in the soil the better. Bacteria, fungi, bugs, grubs and all that microscopic stuff. They are our friends breaking down compounds and releasing nutrients, creating breathing spaces for more microbial life, and allowing passages for water to pass through. Proverbial soil superheroes they are.

Tend to the soil and you tend to the health of not only plants, but yourself too.

Life begets Life.

It’s sad to think a lot of our microbe buddies are often overlooked in a lot of modern day industrial agricultural practises. But things are slowly changing which is a good thing, as researchers and farmers realise and work together to start implementing long term soil nourishing practises. Timely too, because as a resource nitrogen and phosphorus (those two yummy essential plan macro-nutrients) are just about at their limits. 

Research has already shown that we’ve surpassed the nitrogen limit and subsequently outbalanced and impaired the natural nitrogen cycle. For phosphorus, a finite resource which can’t be substituted synthetically, it’s getting harder and harder to find as mines and deposits run out. Soon there won’t be much left.

But we all still gotta eat right?

So now more than ever soil-loving practises are needed, as well as soil-loving people.


The best way in which you can help support our microbe friends is by ensuring the produce you buy and eat is produced using these practises. Go to the farmers market and talk with the farmers about the methods they use, or better yet, ask if you can visit the farm to see it all in action! 

If you grow some of your own produce, then invest in a compost bin or worm farm. Not only are you saving food scraps from landfill, but you are then adding nutrients and microbes into your soil. Hurrah!

So next time your outside, in the wild or in your backyard, take a moment to get down close to the ground and thank the millions of microbes and nutrients and fungi and bugs in the soil for all the good work that they do. 


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